System and method for electrolytic cleaning

ABSTRACT

A method and apparatus for cleaning conductive bodies using an electrolytic cleaning solution. An inverter power source is used to supply a high voltage, low current output for the electrolytic cleaning. The outside surfaces of a metallic body are cleaned by spraying the cleaning solution on to the body and passing a current through the cleaning solution on the conductive body, thereby causing the cleaning solution to electrolytically clean the body. The body is connected to the negative terminal of the power supply. The positive terminal of the power supply is connected to a spray nozzle and causes a current to pass through the spray to the cleaning solution on the body for the electroytic cleaning. Alternatively, a current can be induced in the cleaning solution on the body by placing a grid near the body and connecting the grid to the positive terminal, thereby generating an electric field.

BACKGROUND OF THE INVENTION

[0001] The present invention relates generally to methods, equipment and solutions for electrolytic cleaning. Specifically, the present invention relates to a system and method of electrolytically cleaning conductive bodies using a power supply that has a high voltage and a low current output.

[0002] Bodies capable of conducting electricity, including bodies made entirely of metal and bodies having both metallic and nonmetallic portions, often have outer surfaces that need to be cleaned. Fabricated or machined metal products require cleaning, for example, prior to painting, coating, packaging or shipment. As another example, metal components, which are to be remanufactured for the after-market, almost always require some degree of cleaning.

[0003] Rust, mill scale, embedded chips, core sand, scale, smut, petroleum-derived contaminants, oils, greases, flux, carbonization, nonmetallic coatings, corrosion, oxidation, paint, dirt and the like, may form or be deposited on the surface of the body. These surface deposits or contaminants must be removed so that the body may be recycled and reused, or to prepare the body for subsequent surface treatment. Metal cleaning, including precision cleaning and light/heavy industrial cleaning, is particularly important in industries which are involved in the forming, casting, extruding and machining of ferrous and non-ferrous metals.

[0004] Previously, cleaning of metals was typically accomplished using acidic cleaning solutions, preferably having a pH of 6.0 or less. Acidic solutions were most frequently used because of their relative low cost, and their substantial effectiveness (both in total cleaning ability, cleaning speed and cost) in removing metal oxides, scale and other contaminants prior to pretreatment or painting. Typically, such solutions included mineral acids, chromic acid, carboxylic acids and other organic acids. The use of acidic solutions, due to their very aggressive nature, resulted not only in the removal of the undesirable contaminants on the item being treated, but often had the negative effect of removing material from the item and potentially degrading the tank walls, pump components and other parts of the washer device itself. Further, the solution often had to be replaced due to the change in the pH of the solution over time, and as a result, disposal of the spent solution, which solution would almost certainly be classified as a hazardous substance, was necessary. Additionally, because of the chemical reaction, the spent solution invariably included heavy metals in solution as metallic ions.

[0005] More recently, the metal cleaning industry began to utilize alkaline chemical solutions (having a pH of 8.0 or greater). These solutions typically use detergents and solvents, accompanied by high levels of agitation (such as by ultrasonic bath or high-pressure wash), to effect removal of contaminants. Alkaline cleaners have been formulated with such materials as sodium or potassium hydroxide, carbonate, bicarbonate, phosphate, silicate or other similar materials. The chemical reaction occurs via saponification with water-soluble soaps by neutralization of fatty acid soils. If the pH of the solution is kept between 8.0 and 13.0, these cleaners are somewhat successful in the removal of oils and greases. However, as with acidic solutions, the spent alkaline solutions must be frequently reprocessed, and further, they present similar hazardous waste disposal problems.

[0006] To overcome some of the disadvantages of the above cleaning techniques, a variety of electrolytic cleaning systems were developed. Many of these systems use an electrolyte that is formed of a solution of potassium or sodium salt such as sodium carbonate, potassium carbonate, sodium chloride, sodium nitride, and other similar salts. Most types of electrolytic cleaning are conducted using either a bath or dip system where the body to be cleaned is immersed in the electrolyte or a spray system where the electrolyte is sprayed onto the body to be cleaned. However, other systems for electrolytic cleaning have also been used.

[0007] The prior electrolytic cleaning processes used a rectifier or inverter power supply that output a low voltage, 350 volts or less, and typically an output of less than 50 volts. The power supply in the prior electrolytic cleaning processes typically also had a large current output. The large current output is necessary to generate a high current density in the electrolyte, which was required in many of the prior electrolytic cleaning processes. In addition, many of the prior electrolytic cleaning processes required the electrolyte to be heated for effective electrolytic cleaning.

[0008] Some examples of prior electrolytic cleaning processes that used power supplies with low output voltages are U.S. Pat. No. 3,457,151 to Kortejarvi (0-24 VDC), U.S. Pat. No. 4,493,756 to Degen et al. (0-10 VDC), U.S. Pat. No. 5,776,330 to D'Muhala (0-24 VDC), U.S. Pat. No. 5,227,036 to Gordon (12 VDC), and U.S. Pat. No. 6,045,686 to Fenton et al. (about 30 VDC). Some examples of prior electrolytic cleaning processes that used high current densities are U.S. Pat. No. 6,030,519 to Keller et al. (100 to 2000 amps/dm²), U.S. Pat. No. 3,457,151 to Kortejarvi (10 to 35 amps/ft²), U.S. Pat. No. 4,493,756 to Degen et al. (150 to 450 amps/ft²), U.S. Pat. No. 5,840,173 to Waldmann (3 to 40 amps/dm²), and U.S. Pat. No. 5,104,501 to Okabayashi (1 to 30 amps/dm²).

[0009] The above mentioned conventional methods of cleaning metallic bodies can require extremely high operating temperatures, toxic chemicals and/or highly corrosive liquids and large output currents. Further, many of the techniques discussed above generate hazardous wastes that must be disposed of in compliance with environmental regulations and at high cost. In addition, there are a number of practical shortcomings which are present in the known methods, including limited effectiveness in removing contaminants, short solution life, and the tedious and time-consuming task of altering key variables (such as range of agitation, range of chemical ingredients of the cleaning solution, time and temperature requirements, etc.) in order to determine the optimum level of each variable that will effectively and efficiently accomplish the desired level of cleaning. These variables may vary dramatically, depending on the composition of the body being treated, and on the particular contaminants for which removal is desired. Treatment to clean the bodies should not cause a reaction with the bodies themselves, but rather, should attack only the contaminants and other materials of which removal is desired. Immersing the metallic body in the electrolyte may also be inefficient, as only a small number of bodies may be treated at a time.

[0010] Therefore, what is needed is an improved method and apparatus for cleaning conductive bodies that is quick, efficient and economical. The improved method and apparatus for cleaning conductive bodies should operate at ambient temperature and have an electrolyte that has a substantially neutral pH so that hazardous wastes are not formed, although other electrolytes may be used. In addition, the improved method should be practical and permit the cleaning of a large number of bodies at the same time without attacking the bodies.

BRIEF SUMMARY OF THE INVENTION

[0011] The present invention is directed to a system and method for electrolytically cleaning conductive bodies.

[0012] One embodiment of the present invention is an apparatus for cleaning the surfaces of a conductive body. The apparatus includes a supply of an electrolytic cleaning solution and at least one spray nozzle connected to the supply to permit the electrolytic cleaning solution to flow from the supply to the at least one spray nozzle. The apparatus also has a direct current power source having a high voltage and a low current output. The direct current power source has a positive output terminal and a negative output terminal. The positive output terminal is connected to the at least one spray nozzle and the negative output terminal is connected to the conductive body. Finally, when the direct current power source and the spray nozzle are activated, the electrolytic cleaning solution flowing through the at least one nozzle carries a current to the conductive body to clean the surface. Desirably, after application, the electrolytic cleaning solution can be collected and reused.

[0013] Another embodiment of the present invention is an apparatus for cleaning the surfaces of a conductive body. The apparatus includes a first container having an electrolytic cleaning solution contained therein and a second container connected to the first container to permit the electrolytic cleaning solution to flow between the first container and the second container. At least one spray nozzle is disposed in the second container. The at least one spray nozzle is connected to the first container to permit the electrolytic cleaning solution to flow from the first container to the at least one spray nozzle. The apparatus also includes a direct current power source having a high voltage and a low current output. The direct current power source has a positive output terminal and a negative output terminal. A first grid is disposed in the second container and is connected to said positive output terminal. A second grid is disposed substantially parallel (either horizontally or vertically) to the first grid in the second container. The second grid is connected to the negative output terminal and has the conductive body positioned thereon. Finally, when the direct current power source and the spray nozzle are activated, the electrolytic cleaning solution flowing through the nozzle washes over the conductive body and the first grid and the second grid induce a current in the electrolytic cleaning solution washing over the conductive body to clean the surface.

[0014] Still another embodiment of the present invention is a method of electrolytically cleaning the surfaces of an object. The method includes providing a container having an electrolytic cleaning solution therein and providing a spray washer having at least one spray nozzle. The method also includes connecting the container to the at least one spray nozzle to permit the electrolytic cleaning solution to flow from the container to the at least one spray nozzle and providing an inverter power source having a high voltage and a low current, direct current output. The inverter power source has a positive output terminal and a negative output terminal. The method further includes positioning the object in the spray washer, connecting the positive output terminal to the at least one spray nozzle and connecting the negative output terminal to the object. In addition, the method includes activating the inverter power source and the at least one spray nozzle to flow a current through the electrolytic cleaning solution sprayed by the at least one nozzle on to the object to clean the surfaces of the object and deactivating the inverter power source and the at least one spray nozzle when cleaning is completed. Finally, the method includes removing the object from the spray washer.

[0015] Yet another embodiment of the present invention is a method of cleaning the surfaces of a conductive body. The method includes providing a container having an electrolytic cleaning solution therein and providing a spray washer having at least one spray nozzle. The method also includes connecting the container to the at least one spray nozzle to permit the electrolytic cleaning solution to flow from the container to the at least one spray nozzle and providing an inverter power source having a high voltage and a low current, direct current output. The inverter power source has a positive output terminal and a negative output terminal. The method further includes the steps of connecting the positive output terminal to a first grid positioned in the spray washer and connecting the negative output terminal to a second grid positioned substantially parallel (either horizontally or vertically) to the first grid in the spray washer. The conductive body is positioned on the second grid in the spray washer. The method additionally includes activating the inverter power source and the at least one spray nozzle to induce a current in the electrolytic cleaning solution washing over the conductive body from the at least one spray nozzle to clean the surfaces of the conductive body and deactivating the inverter power source and the at least one spray nozzle when cleaning is completed. Finally, the conductive body is removed from the spray washer.

[0016] Still yet another embodiment of the present invention is an apparatus for cleaning the surface of a conductive body. The apparatus includes a container having an electrolytic cleaning solution therein and a direct current power source having a high voltage and a low current output. The direct current power source has a positive output terminal and a negative output terminal. The negative output terminal is operatively connected to the conductive body. The apparatus also includes an anode in contact with the electrolytic cleaning solution. The anode is connected to the positive output terminal of the power source. Finally, when the conductive body is at least partially immersed in the electrolytic cleaning solution, and when the power source is activated, current flows through the electrolytic cleaning solution to the conductive body to clean the surface.

[0017] The electrolytic spray process permits larger bodies such as transformer cases, transmissions, extruded and sheet steel, boilers and the like to be cleaned on site. It is not necessary to transport the bodies to a bath. Bodies that are too large to be immersed in a bath or which cannot be moved to a bath can be cleaned using an electrolytic spray process.

[0018] If desired, a plurality of metallic bodies can be electrolytically spray cleaned at the same time. The bodies are placed in electrical contact with each other and one body is connected to the negative terminal of the power supply. Electrolyte spray is sprayed onto all the bodies for simultaneous electrolysis and cleaning of all the bodies. The bodies could move through an electrolyte spray on a conveyor belt to spray clean a continuous stream of bodies.

[0019] Temperature ranges for successful cleaning of metallic bodies extend from just above the freezing point of the electrolytic solution to just below the boiling point of the electrolytic solution. The preferred operating temperature of the electrolyte is between about 50 degrees F. and 150 degrees F.

[0020] In each embodiment, a method or apparatus is provided for cleaning items that is more efficient (in cleaning ability, cleaning time, and cost) than existing methods, such as ultrasonic bath or high-pressure aqueous wash systems because of the high voltage, low current power supply that is used, although certain embodiments, such as the submersion embodiments, may be used in conjunction with ultrasonic baths and other embodiments, such as the spray embodiments, may be used in conjunction with high pressure wash systems.

[0021] Other features and advantages of the present invention will be apparent from the following more detailed description of the preferred embodiment, taken in conjunction with the accompanying drawings which illustrate, by way of example, the principles of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

[0022]FIG. 1 is a schematic diagram of one embodiment where a plurality of objects are sprayed with electrolyte for cleaning the exposed surfaces of the objects.

[0023]FIG. 2 is a schematic diagram of a surface of an object being cleaned by the sprayed electrolyte.

[0024]FIG. 3 is a schematic diagram of another embodiment where a plurality of objects are sprayed with electrolyte for cleaning the exposed surfaces of the objects.

[0025]FIG. 4 is a schematic diagram of one embodiment where an object is immersed in an electrolyte for cleaning.

[0026]FIG. 5 is a schematic diagram of another embodiment where an object is immersed in an electrolyte for cleaning.

[0027]FIG. 6 is a schematic diagram of still another embodiment where an object is immersed in an electrolyte for cleaning.

[0028]FIG. 7 is a graph showing the relationship between voltage and time required to remove contaminants of the same type and degree in Examples 1-13.

[0029] Whenever possible, the same reference numbers will be used throughout the figures to refer to the same parts.

DETAILED DESCRIPTION OF THE INVENTION

[0030]FIG. 1 illustrates one configuration of a system for the electrolytic cleaning of objects. One or more objects 100 are located or placed in a spray washer 102 for cleaning the exposed surfaces of the objects 100. The objects 100 are preferably any type of electrically conductive objects, but are typically metallic objects, and can include machined, milled or cast automotive parts, such as engine blocks, manifolds and heads, transformer cases and extruded and sheet steel. The objects 100 are placed in the spray washer 102 to remove any surface contamination present on the objects 100 prior to any subsequent processing or treatment procedures required for the objects 100. The surface contamination present on the objects 100 can include rust, mill scale or oxidation, core sand, embedded chips, paint, oil or grease, dirt and any other similar type of surface contaminant.

[0031] Spray washer 102 includes a reservoir 104 with a supply of cleaning solution 106. The cleaning solution 106 can be any type of electrolytic cleaning solution, including very acidic solutions and very basic solutions. However, the cleaning solution 106 is preferably an aqueous basic solution made of water, disodium phosphate (Na₂ HPO₄) and baking soda (sodium bicarbonate, NaHCO₃) with a pH greater than 7.0 and less than about 10.0 and preferably between 8.0 and 8.5 inclusive.

[0032] The disodium phosphate is preferably food grade disodium phosphate, and more preferably is a granular form of food grade disodium phosphate. Disodium phosphate in the powder form may also be used. The amount of disodium phosphate that is used in the cleaning solution 106 is about 0.0375 pounds per gallon of water to about 1.33 pounds per gallon of water. The amount of baking soda that is used in the cleaning solution 106 is about 0.0125 pounds per gallon of water to about 0.444 pounds per gallon of water. While any combination of disodium phosphate and baking soda within these respective ranges will produce cleaning results without creating any negative environmental implications, it is preferable for the solution to contain approximately three times as much disodium phosphate as baking soda, that is, a ratio of disodium phosphate to baking soda of approximately 3 to 1. Most preferably, approximately 0.075 pounds of disodium phosphate and 0.025 pounds of baking soda are dissolved in each gallon of water to form the cleaning solution 106.

[0033] In addition, when the amount of disodium phosphate is less than 0.15 pounds per gallon of water and the amount of baking soda is less than 0.05 pounds of baking soda per gallon of water, the cleaning solution 106 does not leave a residue of disodium phosphate and baking soda on the object 100 being cleaned. These relatively low concentrations of the cleaning solution 106 also do not have a crystallization problem at lower temperatures due to the oversaturation of the cleaning solution 106.

[0034] A supply or feed line 108 extends from reservoir 104 to a plurality of spray nozzles 110 that spray the cleaning solution 106 on the objects 100. The nozzles 110 are preferably adjustable to provide several different types of output spray characteristics for the cleaning solution 106. For example, the nozzles 110 can have a substantially closed configuration, which results in a narrow or focused output spray of cleaning solution 106, or the nozzles 110 can have a substantially open position, which results in a wide output spray of cleaning solution 106. A supply or feed pump 112 is located in the supply line 108 to pump cleaning solution 106 from the reservoir 104 to the spray nozzles 110. The feed pump 112 can be adjusted to vary the amount of cleaning solution 106 sprayed from the nozzles 110 and to vary the pressure with which the cleaning solution 106 is sprayed from the nozzles 110.

[0035] The feed pump 112 can preferably produce an output of about 25 to 375 gallons per minute (gpm) of cleaning solution 106 at each of the nozzles 110 and an output pressure of cleaning solution 106 of about 10 to 150 pounds per square inch (psi) from each of the nozzles 110. While any combination of output pressure and output flow within these respective ranges will produce cleaning results, it is preferable for the feed pump 112 to generate an output ratio at each of the nozzles 110 of about 1 psi of pressure for about each 2.5 gpm of flow of cleaning solution 106 from each of the nozzles 110. In a preferred embodiment, the feed pump 112 generates an output at each of the nozzles 110 of 100 gpm and 40 psi.

[0036] The number, location and orientation of spray nozzles 110 in the spray washer 102 can be varied to conform to the size and shape of the object or objects 100 being cleaned. The spray nozzles 110 are preferably positioned in the spray washer 102 to assure wetting of the entire surface of the object 100 with cleaning solution 106. The spray nozzles 110 are also preferably positioned at a distance from the object 100 to perform “wash-off” cleaning of the object 100 from the spray and to maintain electrical conductivity in the spray as discussed in more detail below. As the amount of cleaning solution 106 sprayed from the nozzles 110 is increased and the pressure of cleaning solution supplied to the nozzles 110 is increased, the distance between the nozzles 110 and the objects 100 can be increased.

[0037] In an embodiment of the present invention, the objects 100 being cleaned could be placed on a conveyor to move through the electrolyte spray and the spray washer 102. The objects 100 would be exposed to the spray for a sufficient time to be cleaned. Alternatively, the nozzles 110 could move and the objects 100 being cleaned could remain stationary. In still another embodiment, the spray washer 102 could be mounted on a truck to allow spray washing of large or immobile objects such as over-the-road trailers and aircraft. In yet another embodiment, one or more spray nozzles 110 could be attached to a flexible supply line to permit an operator to direct the electrolyte spray where needed.

[0038] After the cleaning solution 106 is sprayed on the objects 100 in the spray washer 102, a drain basin in the spray washer 102 collects sprayed cleaning solution 106. The collected cleaning solution 106 flows through return line 114 to filter 116 for filtering and removal of contaminants. The collected and filtered cleaning solution 106 is then pumped by drain pump 118 through return line 114 to reservoir 104. The cleaning solution 106 can be continuously pumped out of the reservoir 104, sprayed onto the objects 100 and returned to the reservoir 104.

[0039] The electrolytic cleaning process illustrated in FIG. 1 also includes a power supply 120. The power supply 120 has a positive terminal 122 that is connected to the nozzles 110 to form the anodes for the electrolytic cleaning process. In an alternate embodiment, the positive terminal 122 of the power supply 120 can also be connected to a manifold (not shown) for several of the nozzles 110. The power supply 120 also has a negative terminal 124 that is connected to the objects 100 to form the cathodes of the electrolytic cleaning process. Each nozzle 110 (or manifold) can be directly connected to the positive terminal 122 of the power supply 120 or, more preferably, one nozzle 110 (or manifold) can be connected to the positive terminal 122 of the power supply 120 and the remaining nozzles 110 (or manifolds) can be connected or jumpered by jumpers 126 to the nozzle 110 connected to the positive terminal 122 of the power supply 120 as shown in FIG. 1. Similarly, each object 100 can be directly connected to the negative terminal 124 of the power supply 120 or, more preferably, one object 100 can be connected to the negative terminal 124 of the power supply 120 and the remaining objects 100 can be connected or jumpered by jumpers 128 to the object 100 connected to the negative terminal 124 of the power supply 120 as shown in FIG. 1 or can be in contact with the object 100 connected to the negative terminal 124 of the power supply 120. Alternatively, each object 100 in the spray washer 102 can be placed on a grid or plate (not shown) that is connected to the negative terminal 124 of the power supply 120.

[0040] Any suitable power supply can be used to provide the voltage necessary to accomplish electrolytic cleaning. For example, power supply 120 may be one that produces a high voltage direct current (DC) output of 70 volts (V) to over 115 kilovolts (kV). Preferably, the output voltage from the power supply 120 is over 350 V and more preferably over 1000 V. The higher the output voltages from the power supply 120, the higher the cleaning ability of the spray washer 102. In addition, the maximum output voltage output from the power supply 120 can be a large as the power supply 120 can generate. In other words, the maximum voltage output from power supply 120 for electrolytic cleaning is limited only by the mechanical ability of the power supply 120 to generate that desired maximum voltage. With regard to the current output from the power supply 120, the power supply 120 can output a DC current of between 10 amps (when the output voltage is about 140 V) and 0.0005 amps (when the output voltage is about 115 kV). In a preferred embodiment, as the output voltage from power supply 120 is increased, the output current from power supply 120 is decreased. However, it is to be understood that the output current from power supply 120 may stay relatively constant or possibly even increase and still provide effective electrolytic cleaning as the output voltage from power supply 120 is increased. A small current ouptut from power supply 120 is preferred to reduce the possibility of the cleaning solution 106 being heated during the cleaning process. Furthermore, the output voltage and output current from the power supply 120 preferably has substantially constant magnitude throughout the cleaning procedure to provide consistent and effective cleaning. Fluctuations in the output voltage magnitude from power supply 120 can reduce the cleaning effectiveness of the cleaning system 102 during those fluctuations.

[0041] It has been found that inverter power sources or supplies which have traditionally only been used in connection with welding machines and plasma cutters, when used with the methods, equipment and solutions of the present invention, provide excellent results in terms of increased efficiency, effectiveness and cleaning power over known methods for cleaning conductive bodies. For example, power supply 120 can be a Spectrum 3080 power source manufactured by Miller Electric Manufacturing of Appleton, Wis. However, it is to be understood that any other suitable power supply may be used, for example, a rectifier power source.

[0042] Electrolytic cleaning using a conventional rectifier power source requires alternating or reversing the polarity of the cathode and anode, not only to maintain a stable electric field, but also to prevent corrosive deterioration of the cathode and anode, as well as to prevent smut from being attracted to the cathode and anode. While conventional rectifier power sources may be used, in the preferred embodiment an inverter power source is used. It has been found that by using an inverter power source with the cleaning solution, apparatuses and methods of the present invention, as well as with known electrolytic cleaning solutions, apparatuses or methods (whether environmentally friendly or not), the electrolytic cleaning process decreases the time in which debonding and removal of surface materials, contaminants, etc. are removed from metal bodies. Further, there is no need to reverse the polarity of the cathode and anode. As such, the process of the preferred embodiment does not deteriorate or degrade the cathode or anode. Further, an inverter power source allows the cleaning process to be performed at a much lower solution temperature than a conventional rectifier power source. The inverter power source is particularly preferred when electrolytic cleaning via a spray system is desired. In all electrolytic cleaning systems, the higher frequency, more defined direct current produced by an inverter system allows the de-bonding of rust and paint from the metal to a significantly larger degree than that which is achieved using a conventional rectifier power source.

[0043] In an inverter power source from a welding machine, the input alternating current voltage is rectified into an unregulated direct current voltage by means of a diode rectifier. Subsequently, the power converter must take the unregulated direct current and convert it to regulated direct current with a lower voltage level. This is accomplished by a high-frequency bridge, wherein switching causes the generation of a high frequency square wave alternating current. The high frequency alternating current is transferred to the secondary side by means of an isolation transformer, which is then rectified and filtered to produce the regulated high current, low voltage direct current output. By controlling the switching of the high frequency bridge, the output is thereby regulated.

[0044] In contrast, the more preferred inverter power source is from a plasma cutter. The input alternating current (AC) line power is changed into full-wave rectified DC by a silicon-controlled rectifier (SCR) or Integrated Rectifier using thyristors. The output from the SCR is then filtered by capacitors and the peak current from the SCR and the capacitors is limited by inductors. Next, insulated gate bipolar transistor (IGBT) modules convert the DC output into AC through very fast on/off switching of the IGBT modules. This AC can be a high frequency square wave alternating current due to the rapid on/off switching. The AC from the IGBT modules is then used to activate the primary of a transformer. The transformer then supplies power to the cutting circuit from its secondary. The output from the transformer is then rectified using diodes to generate a high voltage, low current DC output.

[0045] The temperature of cleaning solution 106 may range from just above the freezing point of the cleaning solution 106 to just below the boiling point of the cleaning solution 106. The preferred temperature of cleaning solution 106 is between 55 degrees F. and 160 degrees F. An external source of cooling or heating is not provided and the temperature of the cleaning solution 106 does not vary greatly because of the limited amount of electric current which is passing through the cleaning solution 106.

[0046] The streams of electrolyte spray electrically connect the anodes to the metallic body or bodies 100 being cleaned by spray washer 102. It is important that the electrolyte discharged from the nozzles 110 be in continuous streams extending from the anode to the metallic body 100. The length of the streams from the nozzles 110 to the body being cleaned 100 can range from about two inches or less to about eighteen inches depending on the output voltage from the power supply 120. The higher the output voltage from the power supply 120, the larger the distance can be between the nozzles 110 and the object 100 being cleaned. The higher output voltages can maintain the electrical continuity in the stream for the larger distances. In another embodiment of the present invention, when the power supply 120 has an output voltage of over 100 kV, the length of the streams from the nozzles 110 to the body 100 being cleaned can be extended to twenty six inches for the cleaning of rust, oxidation, embedded chips and paint.

[0047]FIG. 2 illustrates in greater detail the electrolytic treatment of the surface of an object 100. Nozzle 110 flows a continuous stream 202 of cleaning solution 106 onto a surface 204 of an object 100. The stream 202 directly impacts or impinges on a small area 206 of surface 204. Impingement area 206 forms part of the cathode and is electrically connected to the anode by stream 202. Electrolytic cleaning takes place on surface area 204.

[0048] Some electrolyte bounces off surface 204 and forms a mist or fog 208 surrounding the impact area 206. The electrolyte mist 208 is sufficiently dense to be electrically conductive and forms a portion of the electrical circuit between the anode and cathode. Other electrolyte 210 from the streams from impact area 206 flows along surface 204 and wets a surface area considerably larger than the area of impingement 206. The surface electrolyte 210 flowing from area 206 remains in fluid connection with electrolyte stream 202 and remains a part of the electrical circuit between the anode and the cathode so that a greatly enlarged surface area is cleaned. Electrolytic activity occurs on surface area 212 of surface 204 in contact with electrolyte mist 208 and the wetted portion of surface 214 in contact with the stream 210. These areas can greatly increase the area of electrolytic cleaning around area 206.

[0049] The surface area cleaned by a stream 202 is not limited to the surface area 206 directly impinged by the stream 202. The nozzles 110 are preferably arranged to maximize the surface areas 212,214 wetted by electrolyte and electrically connected with the anode, and to overlap these areas so that the entire surfaces 204 of the objects 100 are electrolytically cleaned. Wetting of the surfaces 204 of the objects 100 is aided by gravity flow of electrolyte down the objects 100 and by surface tension wetting of recesses and valleys on the surfaces 204 of the objects 100.

[0050] After cleaning of the objects 100 in spray washer 102, power supply 120 is deactivated. The objects 100 are disconnected from the negative terminal 124 of the power supply 120 and are removed from spray washer 102.

[0051]FIG. 3 illustrates another configuration of a system for the electrolytic cleaning of objects. In this embodiment, as shown in FIG. 3, the spray washing system 302 has a spray washer 303 that is placed inside the reservoir 104 of cleaning solution 106. In another embodiment, the spray washer 303 is connected to the reservoir 104 similar to the spray washer 102 in FIG. 1. The positive terminal 122 of the direct current power source 120 is connected, not to each spray nozzle as in FIG. 1, but rather, to a first metal grid, mounting or cage 304 that is provided in the spray washer 303 to form the anode for electrolytic cleaning. The negative terminal 124 of the power source 120 is connected to a second metal grid, mounting or plate 306 to form the cathode for electrolytic cleaning. The second grid, mounting or plate 306 is positioned adjacent and substantially parallel (either in a horizontal direction or a vertical direction) to the first grid or mounting 304. The first grid 304 and the second grid 306 are separated and are not in contact with one another. The second grid 306 is preferably located about 0.25 inches to about 0.5 inches from the first grid 304. The object or body to be cleaned 100 is placed on, and in direct contact with, the second grid 306. The first grid 304 and the second grid 306 are constructed from a conductive material and are preferably perforated steel plates. In addition, the second grid 306 has to be constructed from a material that can also support the weight of the object to be cleaned 100. The first grid 304 and the second grid 306 can be mounted in any suitable way in the spray washer 303 that does not reduce the conductive properties of the first and second grids 304 and 306 and maintains the positions of the first grid 304 and second grid 306. In another embodiment of the present invention, there can be one or more first grids or mountings 304 and second grids or mountings 306 used in the spray washer 303.

[0052] The container 104 holds an amount of cleaning solution 106 that is sufficient to accomplish cleaning of the metal body 100. When the spray washer 303 is positioned within the container 104, as shown in FIG. 3, the level of cleaning solution 106 in container 104 remains below that of the first metal grid 304 so that the cleaning solution 106 does not come into contact with the first metal grid 304, the second metal grid 306 or object 10. In the embodiment where the spray washer 303 is not positioned in the container 104, the level of cleaning solution 106 may be higher.

[0053] Spray washer 303 includes a plurality of spray nozzles 110, and is arranged in relation to the first and second grids 304 and 306 so as to spray the cleaning solution 106 from the spray nozzles 110 towards the object 100. Spray nozzles 110 can be positioned above the object 100, as shown in FIG. 3, or may be positioned below the object 100 (not shown), or both. Additional spray nozzles 110 may be placed around the body 100 to be cleaned in any desired fashion. For example, the spray nozzles 110 can be positioned along the sides of the object 100, that is, in a perpendicular direction to any spray nozzles 110 that are above and/or below the object 100. Further, spray washer 303 can be adapted so as to rotate around the object 100 during cleaning, thereby assuring that cleaning solution 106 is directed at the entire surface area of the object 100.

[0054] A supply line 108 extends from cleaning solution 106 to the spray washer 303. Power supply 120 is energized to generate an electric field with the first and second grids 304 and 306 to induce an electric current in the cleaning solution 106 sprayed onto the surface of the object 100 for electrolytically cleaning the outer surface of the object 100. Feed pump 112 in supply line 108 pumps cleaning solution 106 to spray nozzles 110, which then spray cleaning solution 106 onto the body to be cleaned 100 and wash the object 100 in a continuous stream of cleaning solution 106. Cleaning solution 106 sprayed on the body 100 passes through second grid 306 and first grid 304 and from the spray washer 303, into the bottom of container 104, where the initial supply of cleaning solution 106 is stored. Cleaning solution 106 is then filtered (not shown) and recycled by being continuously drawn through supply line 108 by feed pump 112. In the embodiment of the present invention, where the spray washer 303 is not positioned in the container 104, the spray washer 303 can included a drain to collect the cleaning solution 106 that has been sprayed onto the object 100 and piping to return the cleaning solution 106 to the reservoir 104, in a manner similar to that shown in FIG. 1.

[0055] In another embodiment of the present invention, an insulating material can be positioned directly between first metal grid 304 and second metal grid 306. The insulating material is porous enough to permit cleaning solution 106 to pass through, and yet still provide the necessary separation between the anode and cathode (i.e., first grid 304 and second grid 306).

[0056] The electrolytic cleaning process of the present invention can also be implemented as a dip or bath process. FIGS. 4-6 illustrate different embodiments that can be used for the dip or bath procedures. FIGS. 4-6 illustrate an object 100 immersed in a cleaning solution 106 for cleaning the outer surfaces of the object 100. A power supply direct current source 120 having a positive terminal 122 and a negative terminal 124 is used to supply the power for the electrolytic cleaning process.

[0057] During normal electrolytic cleaning, the power supply 120 is energized for an appropriate time to remove surface contaminants from the object 100. During the cleaning process, bubbles of CO₂ gas are evolved. The bubbles agitate the cleaning solution 106 adjacent the part 100. The agitation may help in mechanically removing surface contaminants and may aid in cleaning the object 100. Agitation of the solution may also be accomplished by a pump or other mechanical method, or by an ultrasonic method No toxic or environmentally hazardous gases are evolved, if the preferred cleaning solution 106 is used. Most surface contaminants removed from the object 100 sink to the bottom of container or vat 104 and form a sludge. Other surface contaminants may float on the top of cleaning solution 106. The sludge and floating residue are physically removed by occasionally collecting each into separate containers. The sludge and floating residue are non-hazardous and may be disposed of through normal channels.

[0058] After completion of the cleaning process, the power supply 120 is deactivated. The object 100 is removed from cleaning solution 106 and disconnected from the negative terminal 124 (if connected). The object 100 may be lightly rinsed with water to remove any loose debris still adhering to the object 100. After rinsing, the outer surfaces of the object 100 have been cleaned and are ready for any post-cleaning surface treatment.

[0059] In the embodiment illustrated in FIG. 4, a nonmetallic container or vat 104 is used to hold the cleaning solution 106 and the object 100. The positive terminal is connected to one or two anodes 402 that are at least partially submersed in the cleaning solution 106. The object 100 is immersed in the cleaning solution 106 and is connected to the negative terminal 124 to form a cathode.

[0060]FIG. 4 illustrates a single object 100 immersed in cleaning solution 106 for cleaning. However, a number of objects 100 in electrical contact with each other can be immersed in cleaning solution 106 for simultaneous cleaning of the objects. One of the objects 100 is connected to the negative terminal 124. The other objects 100 touch the object 100 connected to the negative terminal 124 or form a series of objects 100 that contact one another and include the object 100 connected to the negative terminal 124. Alternatively, vat 104 could be made from stainless steel and connected to the negative terminal 124 of power supply 120 to form the cathode. The objects 100 would contact vat 104 to be connected to the cathode.

[0061] Alternatively, as shown in FIG. 5, a metal grid or plate 502 is positioned in the container 104 and submersed in the cleaning solution 106. The grid 502 is connected to the negative terminal 124 of power source 120. In this alternative embodiment, the object 100 is placed on, and in direct contact with the grid 502. The grid 502 and anodes 402 must not come into contact with one another, and an insulating material (not shown) may be provided between grid 502 and anodes 402 to avoid such contact. The insulating material is positioned so as to allow for sufficient contact between anodes 402 and cleaning solution 106, as well as between grid 502 and cleaning solution 106.

[0062] In still another embodiment, as shown in FIG. 6, the container 104 can be made of metal and connected, such as by bolting, to the positive terminal 122 of power source 120. In this embodiment, the anodes 402 are not used and have been replaced by the connection to the container 104. Grid 502 and container 104 must not come into contact with one another, and an insulating material (not shown) may be provided between grid 502 and container 104 to avoid such contact. The insulating material is positioned so as to allow for sufficient contact between container 104 and cleaning solution 106, as well as between grid 502 and cleaning solution 106.

[0063] When the anodes 402 are made from stainless steel, they generally are not sacrificed during electrolysis and are used continuously. Other types of anodes may act as sacrificial anodes and should be inspected and replaced as necessary.

[0064] In all of the embodiments, the cleaning solution and the process steps used result in a method for removing materials and contaminants from conductive bodies in a manner that is economical and efficient. The present invention removes a wide variety of materials, including mill scale, core sand, embedded chips, rust, scale, smut, petroleum derived contaminants, oils, greases, flux, carbonization, nonmetallic coatings, corrosion, paint, dirt, and oxides, without any degradation or discoloration of the surface of the body being cleaned. All ferrous and nonferrous metals may be treated using the present invention to successfully clean and remove contaminants and other materials therefrom. The preferred cleaning solution is long-lasting, and requires replacement or replenishment on a very infrequent basis. Further, by utilizing an inverter power source from a plasma cutter, the process of the present invention accomplishes a level of cleaning which is equal to or better than known electrolytic cleaning techniques (including those techniques which today are considered to be not environmentally friendly, caustic, inefficient, non-economical, etc.), and does so in a manner which is equal to or faster than known methods.

[0065] The following examples of cleaning metallic bodies further illustrate the invention.

EXAMPLE 1

[0066] An electrolyte solution was prepared by dissolving disodium phosphate at a concentration of about 0.75 pounds per 10 gallons of water and sodium bicarbonate at a concentration of about 0.25 pounds per 10 gallons of water. The volume of electrolyte was sufficient to fill a 50-gallon holding tank attached to a pump supplying a spray system mounted in another tank. The pump was configured to provide an output of 100 gallons per minute (gpm) at a pressure of 40 pounds per square inch (psi) of electrolyte from each of a series of spray nozzles in the spray system. A head casting contaminated with core sand was placed in the tank for cleaning by the spray system at a distance of two inches from the series of spray nozzles. An inverter power supply from a plasma cutter was used to supply 140 volts (V) and 10 amperes (A) to the spray system. The negative terminal of the inverter power supply was connected to the casting. The positive terminal of the inverter power supply was connected to the series of nozzles positioned to flow streams of electrolyte on the casting. The power supply was activated along with the spray system. The stream pattern of the nozzles wetted all of the casting surfaces. Excess electrolyte was drained from the tank, filtered and pumped to the pump holding tank for reuse. After 18 minutes, the core sand was released from the casting and the bare metal exposed. The power supply and spray system were deactivated and the casting removed.

EXAMPLE 2

[0067] The same arrangement as in Example 1 was used, except that the inverter power supply was used to supply 115 kilovolts (kV) and 0.0005 A to the spray system and the casting was placed at a distance of 18 inches from the series of spray nozzles. After 220 seconds, the core sand was released from the casting and the bare metal exposed.

EXAMPLE 3

[0068] The same arrangement as in Example 1 was used, except that the head casting was contaminated with mill scale. After 17 minutes, the mill scale was removed from the casting and the bare metal exposed.

EXAMPLE 4

[0069] The same arrangement as in Example 3 was used, except that the inverter power supply was used to supply 250 V and 1.76 A to the spray system and the casting was placed at a distance of 4 inches from the series of spray nozzles. After 14.5 minutes, the mill scale was removed from the casting and the bare metal exposed.

EXAMPLE 5

[0070] The same arrangement as in Example 3 was used, except that the inverter power supply was used to supply 500 V and 0.976 A to the spray system and the casting was placed at a distance of 6.5 inches from the series of spray nozzles. After 12.75 minutes, the mill scale was removed from the casting and the bare metal exposed.

EXAMPLE 6

[0071] The same arrangement as in Example 3 was used, except that the inverter power supply was used to supply 115 kV and 0.0005 A to the spray system and the casting was placed at a distance of 18 inches from the series of spray nozzles. After 2.15 minutes, the mill scale was removed from the casting and the bare metal exposed.

EXAMPLE 7

[0072] The same arrangement as in Example 1 was used, except that the casting was contaminated with embedded chips and the inverter power supply was used to supply 70 V and 15.7 A to the spray system. After 12 minutes, the embedded chips were removed from the casting and the bare metal exposed.

EXAMPLE 8

[0073] The same arrangement as in Example 7 was used, except that the inverter power supply was used to supply 250 V and 1.76 A to the spray system and the casting was placed at a distance of 4 inches from the series of spray nozzles. After 9.5 minutes, the embedded chips were removed from the casting and the bare metal exposed.

EXAMPLE 9

[0074] The same arrangement as in Example 7 was used, except that the inverter power supply was used to supply 500 V and 0.976 A to the spray system and the casting was placed at a distance of 6.5 inches from the series of spray nozzles. After 7 minutes, the embedded chips were removed from the casting and the bare metal exposed.

EXAMPLE 10

[0075] The same arrangement as in Example 7 was used, except that the inverter power supply was used to supply 115 kV and 0.0005 A to the spray system and the casting was placed at a distance of 18 inches from the series of spray nozzles. After 1.3 minutes, the embedded chips were removed from the casting and the bare metal exposed.

EXAMPLE 11

[0076] The same arrangement as in Example 1 was used, except that the casting was contaminated with oxides and rust and the inverter power supply was used to supply 100 V and about 10 A to the spray system. After 2 minutes, the oxides and rust were removed from the casting and the bare metal exposed.

EXAMPLE 12

[0077] The same arrangement as in Example 11 was used, except that the inverter power supply was used to supply 500 V and 0.976 A to the spray system and the casting was placed at a distance of 6.5 inches from the series of spray nozzles. After 15 seconds, the oxides and rust were removed from the casting and the bare metal exposed.

EXAMPLE 13

[0078] The same arrangement as in Example 11 was used, except that the inverter power supply was used to supply 115 kV and 0.0005 A to the spray system and the casting was placed at a distance of 18 inches from the series of spray nozzles. The oxides and rust were removed from the casting and the bare metal exposed essentially on contact by the electrolytic spray.

[0079]FIG. 7 shows the relationship between voltage and time for removal of the various contaminants set forth in Examples 1-13. Generally, increasing the voltage decreases the cleaning time. Below 1 kV, the relationship is substantially linear for contaminants of the same type and degree. As the voltage increases, the relationship will become asymptotic. However, higher voltages may be beneficial and desirable when the scale or material to be removed is very heavy or severe.

EXAMPLE 14

[0080] A second test was conducted at Ingersoll Cinetic facilities in Livonia, Mich. using a “Halo” test cell outfitted with the present invention. An electrolyte solution was prepared by dissolving disodium phosphate at a concentration of about 0.50 pounds per 1 gallons of water and sodium bicarbonate at a concentration of about 0.25 pounds per 1 gallons of water. The volume of electrolyte was sufficient to fill a 500-gallon holding tank attached to a pump supplying the Halo test cell. The pump was configured to provide an output of 250 gallons per minute (gpm) and a pressure of 150 pounds per square inch (psi) of electrolyte to a series of 32 spray nozzles in the Halo test cell. A “cast iron” V-6 cylinder head was soiled with embedded chips and oil to simulate the part after a milling process. The cylinder head was placed in the Halo test cell with the joint face down and the rear leading at a distance of four inches from the series of spray nozzles for cleaning by the Halo test cell. An inverter power supply from a plasma cutter was used to supply 500 volts (V) and 2.9 amperes (A) to the Halo test cell. The negative terminal of the inverter power supply was connected to the cylinder head. The positive terminal of the inverter power supply was connected to the series of nozzles positioned to flow streams of electrolyte on the cylinder head. The power supply was activated along with the Halo test cell, which resulted in the series of spray nozzles being oscillated over the cylinder head. The stream pattern of the nozzles wetted all of the cylinder head surfaces. After 1 minute, 28 seconds, the power supply and the Halo test cell were deactivated and the cylinder head was removed with no rinsing. A metal port test was conducted on the cylinder head as removed from the Halo test cell and with no rinsing of the cylinder head. The metal port test revealed that no oil or metallic contaminants remained on the cylinder head. The only residue present on the cylinder head was disodium phosphate from the electrolyte.

[0081] While the invention has been illustrated and described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims. 

What is claimed is:
 1. An apparatus for cleaning surfaces of a conductive body, said apparatus comprising: a supply of electrolytic cleaning solution; at least one spray nozzle in fluid communication with said supply, so that said electrolytic cleaning solution flows from said supply to said at least one spray nozzle; a direct current power source having a high voltage and a low current output, said direct current power source having a positive output terminal and a negative output terminal, said positive output terminal being connected to said at least one spray nozzle and said negative output terminal being connected to said conductive body; and wherein when said direct current power source and said spray nozzle are activated, said electrolytic cleaning solution flowing through said at least one nozzle carries a current to said conductive body to clean said surface.
 2. The apparatus of claim 1 wherein said direct current power source is an inverter power source.
 3. The apparatus of claim 2 wherein said high voltage output by said inverter power source is greater than 350 volts.
 4. The apparatus of claim 3 wherein said high voltage output by said inverter power source is at least 500 volts.
 5. The apparatus of claim 4 wherein said high voltage output by said inverter power source is at least 1000 volts.
 6. The apparatus of claim 5 wherein said high voltage output by said inverter power source is at least 100 kilovolts.
 7. The apparatus of claim 1 wherein said electrolytic cleaning solution comprises disodium phosphate and sodium bicarbonate dissolved in water.
 8. The apparatus of claim 7 wherein said electrolytic cleaning solution comprises about 0.0375 to 1.33 pounds of disodium phosphate and about 0.0125 to 0.445 pounds of sodium bicarbonate per gallon of water.
 9. The apparatus of claim 7 wherein said electrolytic cleaning solution comprises a ratio of about three times as many pounds per gallon of water of disodium phosphate as pounds per gallon of water of sodium bicarbonate.
 10. The apparatus of claim 9 wherein said electrolytic cleaning solution comprises about 0.075 pounds of disodium phosphate and about 0.025 pounds of sodium bicarbonate per gallon of water.
 11. The apparatus of claim 1 further comprising a pump to transport said electrolytic cleaning solution between said supply and said at least one spray nozzle.
 12. The apparatus of claim 11 wherein said pump generates an output ratio of electrolytic cleaning solution at said at least one spray nozzle of about 2.5 gallons per minute of flow for about 1 pound per square inch of pressure.
 13. The apparatus of claim 12 wherein said pump generates a flow of about 25 to 375 gallons per minute of electrolytic cleaning solution at said at least one spray nozzle.
 14. The apparatus of claim 13 wherein said pump generates a flow of about 100 gallons per minute of electrolytic cleaning solution at said at least one spray nozzle.
 15. The apparatus of claim 12 wherein said pump generates a pressure of about 10 to 150 pounds per square inch of electrolytic cleaning solution from said at least one spray nozzle. 4
 16. The apparatus of claim 15 wherein said pump generates a pressure of 40 pounds per square inch of electrolytic cleaning solution from said at least one spray nozzle.
 17. The apparatus of claim 1 wherein the pH of said electrolytic cleaning solution is about 7.0 to about 9.0.
 18. The apparatus of claim 17 wherein said pH is about 8.0 to about 8.5.
 19. An apparatus for cleaning surfaces of a conductive body, said apparatus comprising: a first container having an electrolytic cleaning solution therein; a second container connected to said first container to permit said electrolytic cleaning solution to flow between said first container and said second container; at least one spray nozzle positioned in said second container, said at least one spray nozzle connected to said first container to permit said electrolytic cleaning solution to flow from said first container to said at least one spray nozzle; a direct current power source having a high voltage and a low current output, said direct current power source having a positive output terminal and a negative output terminal, a first grid positioned in said second container, said first grid being connected to said positive output terminal; a second grid positioned in said second container substantially parallel to said first grid, said second grid connected to said negative output terminal, and wherein said conductive body being positioned on said second grid; and wherein when said direct current power source and said spray nozzle are activated, said electrolytic cleaning solution flowing through said at least one nozzle washes over said conductive body and said first grid and said second grid induce a current in said electrolytic cleaning solution washing over said conductive body to clean said surface.
 20. The apparatus of claim 19 wherein said direct current power source is an inverter power source.
 21. The apparatus of claim 20 wherein said high voltage output by said inverter power source is greater than 350 volts.
 22. The apparatus of claim 21 wherein said high voltage output by said inverter power source is at least 500 volts.
 23. The apparatus of claim 22 wherein said high voltage output by said inverter power source is at least 1000 volts.
 24. The apparatus of claim 23 wherein said high voltage output by said inverter power source is at least 100 kilovolts.
 25. The apparatus of claim 19 wherein said electrolytic cleaning solution comprises disodium phosphate and sodium bicarbonate dissolved in water.
 26. The apparatus of claim 25 wherein said electrolytic cleaning solution comprises about 0.0375 to 1.33 pounds of disodium phosphate and about 0.0125 to 0.445 pounds of sodium bicarbonate per gallon of water.
 27. The apparatus of claim 26 wherein said electrolytic cleaning solution comprises a ratio of about three times as many pounds per gallon of water of disodium phosphate as pounds per gallon of water of sodium bicarbonate.
 28. The apparatus of claim 27 wherein said electrolytic cleaning solution comprises about 0.075 pounds of disodium phosphate and about 0.025 pounds of sodium bicarbonate per gallon of water.
 29. The apparatus of claim 19 further comprising a pump to transport said electrolytic cleaning solution from said first container to said at least one spray nozzle.
 30. The apparatus of claim 29 wherein said pump generates an output ratio of electrolytic cleaning solution of about 2.5 gallons per minute of flow for about 1 pound per square inch of pressure at said at least one spray nozzle.
 31. The apparatus of claim 30 wherein said pump generates a flow of about 25 to 375 gallons per minute of electrolytic cleaning solution at said at least one spray nozzle.
 32. The apparatus of claim 31 wherein said pump generates a flow of about 100 gallons per minute of electrolytic cleaning solution at said at least one spray nozzle.
 33. The apparatus of claim 30 wherein said pump generates a pressure of about 10 to 150 pounds per square inch of electrolytic cleaning solution from said at least one spray nozzle.
 34. The apparatus of claim 33 wherein said pump generates a pressure of 40 pounds per square inch of electrolytic cleaning solution from said at least one spray nozzle.
 35. The apparatus of claim 19 wherein the pH of said electrolytic cleaning solution is about 7.0 to about 10.0.
 36. The apparatus of claim 35 wherein said pH is about 8.0 to about 8.5.
 37. The apparatus of claim 19 wherein said second grid is disposed about 0.25 inches to about 0.50 inches above said first grid.
 38. A method of electrolytically cleaning surfaces on an object comprising the steps of: providing a container having an electrolytic cleaning solution therein; providing a spray washer having at least one spray nozzle; connecting the container to the at least one spray nozzle to cause the electrolytic cleaning solution to flow from the container to the at least one spray nozzle; providing an inverter power source having a high voltage and a low current, direct current output, the inverter power source having a positive output terminal and a negative output terminal; positioning the object in the spray washer; connecting the positive output terminal to the at least one spray nozzle; connecting the negative output terminal to the object; activating the inverter power source and the at least one spray nozzle to flow a current through the electrolytic cleaning solution sprayed as a continuous stream by the at least one nozzle to the object, to clean the surfaces of the object; deactivating the inverter power source and the at least one spray nozzle when cleaning is completed; and removing the object from the spray washer.
 39. The method of claim 38 further comprising the step of setting the high voltage output from the inverter power source to be greater than 350 volts.
 40. The method of claim 38 further comprising the step of setting the high voltage output from the inverter power source to be at least 500 volts.
 41. The method of claim 38 further comprising the step of setting the high voltage output from the inverter power source to be at least 1000 volts.
 42. The method of claim 38 further comprising the step of setting the high voltage output from the inverter power source to be at least 100 kilovolts.
 43. The method of claim 38 wherein said step of providing a container having an electrolytic cleaning solution further comprises the step of forming the electrolytic cleaning solution by dissolving disodium phosphate and sodium bicarbonate in water.
 44. The method of claim 43 wherein said step of forming the electrolytic cleaning solution further comprises the step of dissolving about 0.0375 to 1.33 pounds of disodium phosphate and about 0.0125 to 0.445 pounds of sodium bicarbonate per gallon of water.
 45. The method of claim 44 wherein said electrolytic cleaning solution comprises a ratio of about three times as many pounds per gallon of water of disodium phosphate as pounds per gallon of water of sodium bicarbonate.
 46. The method of claim 38 wherein the pH of said electrolytic cleaning solution is about 7.0 to about 10.0.
 47. The method of claim 38 further comprising: a pump to transport said electrolytic cleaning solution from said container to the at least one spray nozzle; setting the pump to generate a flow of about 25 to 375 gallons per minute of electrolytic cleaning solution at the at least one spray nozzle; and setting the pump to generate a pressure of about 10 to 150 pounds per square inch of electrolytic cleaning solution from the at least one spray nozzle.
 48. The method of claim 47 further comprising the step of setting the pump to generate an output ratio of electrolytic cleaning solution at the at least one spray nozzle of about 2.5 gallons per minute of flow for about 1 pound per square inch of pressure.
 49. A method of cleaning surfaces of a conductive body, said method comprising the steps of: providing a container having an electrolytic cleaning solution therein; providing a spray washer having at least one spray nozzle; connecting the container to the at least one spray nozzle to permit the electrolytic cleaning solution to flow from the container to the at least one spray nozzle; providing an inverter power source having a high voltage and a low current, direct current output, the inverter power source having a positive output terminal and a negative output terminal; connecting the positive output terminal to a first grid positioned in the spray washer; connecting the negative output terminal to a second grid positioned substantially parallel to said first grid in the spray washer; positioning the conductive body on the second grid in the spray washer; activating the inverter power source and the at least one spray nozzle to induce a current in the electrolytic cleaning solution washing over the conductive body from the at least one spray nozzle to clean the surfaces of the conductive body; deactivating the inverter power source and the at least one spray nozzle when cleaning is completed; and removing the conductive body from the spray washer.
 50. An apparatus for cleaning the surface of a conductive body, said apparatus comprising: a container having an electrolytic cleaning solution therein; a direct current power source having a high voltage and a low current output, said direct current power source having a positive output terminal and a negative output terminal, and said negative output terminal being operatively connected to said conductive body; and an anode in contact with said electrolytic cleaning solution, wherein said anode is connected to the positive output terminal of said power source; and wherein said conductive body is at least partially immersed in said electrolytic cleaning solution, and when said power source is activated, current flows through said electrolytic cleaning solution and to said conductive body to clean said surface.
 51. The apparatus of claim 50 wherein said anode is immersed in said electrolytic cleaning solution.
 52. The apparatus of claim 50 wherein said positive output terminal is connected to said container to form said anode.
 53. The apparatus of claim 50 wherein said negative output terminal is directly connected to said conductive body.
 54. The apparatus of claim 50 further comprising a grid capable of conducting electricity, said grid being at least partially immersed in said cleaning solution, said grid being disposed in at least partial contact with said conductive body and said grid being connected to said negative output terminal.
 55. The apparatus of claim 50 wherein said direct current power source is an inverter power source.
 56. The apparatus of claim 55 wherein said high voltage output by said inverter power source is greater than 350 volts.
 57. The apparatus of claim 56 wherein said high voltage output by said inverter power source is at least 500 volts.
 58. The apparatus of claim 57 wherein said high voltage output by said inverter power source is at least 1000 volts.
 59. The apparatus of claim 58 wherein said high voltage output by said inverter power source is at least 100 kilovolts.
 60. The apparatus of claim 50 wherein said electrolytic cleaning solution comprises disodium phosphate and sodium bicarbonate dissolved in water.
 61. The apparatus of claim 60 wherein said electrolytic cleaning solution comprises about 0.0375 to 1.33 pounds of disodium phosphate and about 0.0125 to 0.445 pounds of sodium bicarbonate per gallon of water.
 62. The apparatus of claim 61 wherein said electrolytic cleaning solution comprises a ratio of about three times as many pounds per gallon of water of disodium phosphate as pounds per gallon of water of sodium bicarbonate.
 63. The apparatus of claim 62 wherein said electrolytic cleaning solution comprises about 0.075 pounds of disodium phosphate and about 0.025 pounds of sodium bicarbonate per gallon of water.
 64. The apparatus of claim 50 wherein the pH of said electrolytic cleaning solution is about 7.0 to about 10.0.
 65. The apparatus of claim 64 wherein said pH is about 8.0 to about 8.5.
 66. An apparatus for cleaning surfaces of a conductive body, said apparatus comprising: a container having an electrolytic cleaning solution therein; at least one spray nozzle connected to said container to permit said electrolytic cleaning solution to flow from said container to said at least one spray nozzle; an inverter power source having a high voltage and a low current output, said inverter power source having a positive output terminal and a negative output terminal, said positive output terminal being connected to said at least one spray nozzle and said negative output terminal being connected to said conductive body; and wherein when said inverter power source and said spray nozzle are activated, said electrolytic cleaning solution flowing through said at least one nozzle carries a current to said conductive body to clean said surface.
 67. The apparatus of claim 66 wherein said high voltage output by said inverter power source is at least 1000 volts.
 68. The apparatus of claim 67 wherein said high voltage output by said inverter power source is at least 100 kilovolts.
 69. The apparatus of claim 66 wherein said electrolytic cleaning solution comprises disodium phosphate and sodium bicarbonate dissolved in water in a ratio of about three times as many pounds per gallon of water of disodium phosphate as pounds per gallon of water of sodium bicarbonate.
 70. The apparatus of claim 66 further comprising a pump to transport said electrolytic cleaning solution between said container and said at least one spray nozzle, wherein said pump generates an output ratio of electrolytic cleaning solution at said at least one spray nozzle of about 2.5 gallons per minute of flow for about 1 pound per square inch of pressure.
 71. The apparatus of claim 70 wherein said pump generates a flow of about 25 to 375 gallons per minute of electrolytic cleaning solution at said at least one spray nozzle and a pressure of about 10 to 150 pounds per square inch of electrolytic cleaning solution from said at least one spray nozzle. 